No, the US never truly committed to winning in the Middle East, or they could have easily wiped out any resistance. What about Iraq - we obliterated their standing army, which had much more advanced weapons than guns. How is an assault rifle going to help against a tank, jet fighter or bomber?
While it was the intended purpose (intended being the key word), the Founding Fathers never envisioned the weaponry that's available today. You're delusional if you think that rifles and handguns are going to stop the full might of the US Army, or any other modern industrialized army for that matter. Heck, the US could just lob missiles from hundreds of miles away even, so how is a gun going to help?
The 2nd Amendment also clearly states "as part of a well-regulated militia", which you guys conveniently leave out all of the time.